To add new media to the system, the user must simply copy the files to the root directory of
the Compact Flash card. Media should be presented in the following formats:
Text: ASCII encoded files with the .txt extension
Images: To display properly, images must use 15-bit color, padded to 16 bits as
follows (bit 15 being the most-significant bit):
Bit 15 - Unused
Bits [14:10] - Red
Bits [9:5] - Green
Bits [4:0] - Blue
Also, images must be at most 128 pixels wide by 124 pixels long, stored in the .bmp extension.
Audio: Uncompressed .wav format, encoded at a sample rate of 48 KHz,
with stereo, 8-bit samples.
Programs: Programs must be assembled into p37x object code and stored in the .obj
format, as produced by the PennSim simulator. Programs that run on top of the operating
system must begin at memory address x3000. These programs should save the state of the
system's registers on startup and restore these registers upon termination. To return control
of the processor to the operating system, these programs simply jump to the address stored in
register R7, which is set by the OS upon calling the new program. Programs that replace the
operating system must begin at memory address x200. These programs return control to the OS
by clearing the boot flag (register R4), and jumping to address xFF00, which is the boot ROM.
If any program misbehaves, preventing the OS from regaining control of the processor, the
operating system can be restarted by pressing the system's reset button.